JP2793398B2 - Ring circuit monitoring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for monitoring a ring circuit, and more particularly to a method for monitoring disconnection of a submarine cable when communication stations are connected by a submarine cable or the like. And a method for monitoring a ring circuit that is suitable.

[0002]

2. Description of the Related Art In a three-station system for performing submarine cable communication as shown in FIG. 3, monitoring activities using a monitoring activity flag have been conventionally performed.

[0003] The operation of the monitoring activity flag is performed in monitoring the status of the repeater. If monitoring activities are performed simultaneously from the stations at both ends of the line, the repeater receives commands from both stations at the same time, and confusion is likely to occur, such as detecting an activity command as an error. In order to prevent this, in one line unit, the repeater monitoring execution right is given to only one station at a time, and the entire system is operated so that only one repeater monitoring execution right is given.

[0004] The execution right is obtained by issuing a monitoring activity flag assigned to each station to the opposing station to indicate the intention to execute the monitoring activity.
For example, in the case of a three-station configuration (stations A, B, and C), the monitoring activity flag is set so that the monitoring activity of station A is started after the other two stations, that is, stations B and C, recognize the monitoring activity. It was operated like. That is, the monitoring activity flag issued from the station A is “station A → station B → station C → station A” or “station A → C
The data was transferred to the station A along the clockwise or counterclockwise route "station → station B → station A".

[0005] In the case of submarine communication, the monitoring activity flag between stations uses the communication cable itself as a transfer line. However, if a failure such as a communication cable disconnection occurs, the above-described clockwise / counterclockwise monitoring activity flag transfer between stations becomes impossible, so that a conventional loop line monitoring device uses a backup by a modem or a public line. Needed a line.

[0006]

In the above conventional ring line monitoring apparatus, there is a problem that a backup line is required for transferring a monitoring activity flag, which is inefficient. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a method of monitoring a ring circuit capable of transmitting an intention to perform a monitoring activity without requiring a backup line.

[0007]

In order to achieve the above object, a method for monitoring a ring circuit according to the present invention comprises connecting a plurality of communication stations in a ring circuit and monitoring the ring circuit for an abnormality. In the monitoring method , the communication station
When a lag request is made, the time being monitored
The first monitoring activity flag is
And the corresponding station sets the first monitoring activity flag.
When receiving, which station is the first monitoring activity flag received?
To determine which line is being issued and send it to the issuing station.
Same as the first monitoring activity flag received only for
A second monitoring activity flag is issued, and the first monitoring activity flag is output.
The issuing station of the lag is before issuing from the corresponding opposite station.
The second monitoring activity flag is received and the
Second monitoring activity flag that is identical to one monitoring activity flag
Is received from the corresponding station .

[0008]

In the invention configured as described above, the adjacent station
The intermediary arbitration means establishes a line connecting adjacent stations between adjacent stations.
Requests for arbitration for targeted monitoring
Means requesting the start of surveillance activities and
When a request signal indicating a line is issued to an adjacent station, an authorized issuing source is issued.
The stage indicates that it is possible to monitor the target line and
Authorized to the issuing station when receiving the above request signal
Signal and the supervisory control unit issues a request signal to the adjacent station
Monitoring action is started if an authorization signal is received after
Let

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart illustrating a processing procedure of a method for monitoring a loop line according to an embodiment of the present invention. In the figure, when a request for issuing a monitoring activity flag is made at a communication station (step 1), a first monitoring activity flag is issued to an opposite station sharing a line (cable) to be monitored (step 1). Step 2).

[0010] appropriate counter station receives the first monitoring activity flag (step 3), is issued from the first surveillance flags which station receiving determining what the line symmetric to (step 4), originating A second monitoring activity flag that is the same as the first monitoring activity flag received only for the departure station is issued (step 5). The issuing station of the first monitoring activity flag in step 2 receives the second monitoring activity flag issued in step 5 (step 6), and is the same as the first monitoring activity flag issued from its own station. It is confirmed that the second monitoring activity flag has been received from the corresponding station (step 7). This processing procedure is provided in all communication stations.

[0011] Next, the operation of this embodiment having the above structure. Now, in the three-station system shown in FIG. 3, it is assumed that station A is going to carry out a monitoring activity on the line between stations A and B. The first monitoring activity flag SV-A (AB) 8 issued from the station A to the station B is
It is confirmed by the station B that the signal originated from the station A and that the line between the stations A and B is the target, and the station B issues the second monitoring activity flag SV-A (AB) 9. Issued to station A, which is the originating station.

The station A receives the second monitoring activity flag SV-A (AB) 10 transmitted from the station B, and the first monitoring activity flag SV-A (AB) issued from its own station. It is confirmed that the second monitoring activity flag SV-A (AB) 10, which is the same as that of 8, is transmitted from the destination station at the destination. During this series of processing, station C does not sense. FIG. 2 shows the flow of this processing procedure in each station. Since the request for issuing the monitoring activity flag has been made at the station A (step S1).
A), a first monitoring activity flag SV-A (AB) is issued to the station B (step S2A).

The station B has a first monitoring activity flag SV-A (A
-B) (step S3B), and after judging from which station the first monitoring activity flag SV-A (AB) is issued and which line is targeted (step S4).
B) The second monitoring activity flag SV-A (AB) is issued only to the issuing station A (step S5).
B).

The station A receives the second monitoring activity flag SV-A ( AB) transmitted from the station B (step S6).
A), first monitoring activity flag SV-A issued from the own station
Second monitoring activity flag SV-A identical to (AB)
It is confirmed that (AB) has been received from the station B (step S7A). Even during these processes, the station C does not sense.

[0015]

As described above, according to the present invention, the monitoring activity flag is transmitted and received between communication stations on a one-to-one basis.
Therefore, if the flag cannot be transferred, it can be determined that the line has been disconnected, and if the flag can be transferred, the monitoring activity can be started to determine the presence or absence of another abnormality. That is, it is possible to provide a method of monitoring a ring circuit that can monitor a line even when there is no backup line.

Further , since the monitoring activity flags are exchanged in units of both end stations of the line to be monitored, the monitoring activity can be performed on a plurality of lines at once.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a processing procedure of a method for monitoring a ring circuit according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing procedure in each communication station.

FIG. 3 is a block diagram showing loop-connected lines.

[Explanation of symbols]

 8-10: Monitoring activity flag

Continuation of the front page (56) References JP-A-5-91117 (JP, A) JP-A-2-239744 (JP, A) JP-A-2-158249 (JP, A) JP-A-63-36636 (JP) , A) JP-A-53-87107 (JP, A) Shimura Shizuichi, "International Undersea Cable Communication", KDD Engineering and Consulting, p. 394-"Chapter 5 System Test", March 1979 25 (58) Fields surveyed (Int. Cl. ⁶ , DB name) H04L 12/42-12/437 H04L 13/00 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. A communication system in which a plurality of communication stations are connected in a ring circuit.
Allowed, monitoring for monitoring the presence of abnormality in the annular channel
In the method , when a request for issuing a monitoring activity flag is made at a communication station, the monitoring is performed.
For adjacent opposing stations sharing the line that is the target of the activity
A first monitoring activity flag is issued, and the corresponding opposite station receives the first monitoring activity flag,
Which station received the first monitoring activity flag
Judge which line is the target and receive it only for the originating station.
A second monitoring activity that is identical to the first monitoring activity flag
And the issuing station of the first monitoring activity flag determines that the corresponding
Receiving the second monitoring activity flag issued from the remote station
And the same as the first monitoring activity flag issued from the own station.
Received the second monitoring activity flag from the opposite station
A ring circuit monitoring method characterized by confirming the following.